What Windows version to choose for VPS?

I can choose between:

Windows Server 2003 R2 SP2 Enterprise 64bit
Windows Server 2008 R2 Standard
Windows Server 2008 R2 Enterprise
Windows 7 Ultimate 32bit

Not sure I really need a 64bit platform as I don't require more than 1GB of memory at this point and I doubt I'll ever need to go past 2GB on this specific VPS.

So which one would you recommend and why?

I would suggest to take 2008 R2 Standard because it need less resources. If you don't need Enterprise Features, Standard is enough.

W7 Ultimate is not so save as a server OS.

Windows Server 2008 R2 Standard
best wud be that one imo.

Server 2003 has been known to be very stable. If you just want to run SEO tools and such choose Server 2003 or XP Professional.

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I'm a bit old school and still run sbs 2003 at work and on other servers I've worked on. Saying that, my VPS is 2008 and I much prefer it for day to day use. It's pretty much windows 7 in a fancy frock with more twiddly bits.

Windows Server 2008 R2 Standard probable the best choice
minimum ram 2GB .
it is probable the best choice
don't take the 64 bits version !

Take some WS2008 and pay attention to cpu power and how they manage backups.Also gather informations about restrictions(terminal sessions,cpu quota ...Those are more important issues